Simultaneous LC-MS/MS Analysis of Bromate, Chlorate, Dalapon, and Haloacetic Acids in Drinking Water Samples using LCMS-8060RX

Significance of the topic

The formation of disinfection byproducts (DBPs) such as haloacetic acids (HAAs), bromate, chlorate and the herbicide dalapon in chlorinated or brominated drinking water is a critical public-health and regulatory issue. Rapid, accurate and sensitive analytical methods are required for routine monitoring at regulatory levels (including NPDWR-relevant concentrations) with sufficient throughput for water utilities and contract laboratories. This study demonstrates a fast LC-MS/MS approach that reduces runtime and sample preparation relative to EPA Method 557 while maintaining sensitivity and reproducibility.

Objectives and study overview

• Develop and evaluate a reverse-phase LC-MS/MS method on the Shimadzu LCMS-8060RX for simultaneous quantification of bromate, chlorate, dalapon and nine haloacetic acids (HAAs) in drinking water.
• Achieve NPDWR-relevant sensitivity and accuracy with improved throughput (15-minute runtime) versus the regulated IC-ESI-MS/MS method (56 minutes).
• Validate performance using reagent water, municipal tap water, and the laboratory fortified synthetic sample matrix (LFSSM) described in EPA Method 557.

Methodology

• Analytes: bromate, chlorate, dalapon and nine HAAs (including mono-, di-, tri-halogenated acetic acids and mixed halogen species such as BCAA, BDCAA, CDBAA, DBAA, DCAA, MBAA, MCAA, TBAA and TCAA).
• Chromatography: Nexera X3 HPLC with a C18 analytical column; mobile phases A = 0.2% formic acid in water, B = 0.2% formic acid in methanol; gradient elution; flow 0.5 mL/min; oven 40 °C; injection volume 20 µL; total runtime 15 min.
• Mass spectrometry: Shimadzu LCMS-8060RX in negative-ion mode (CoreSpray); source and gas parameters reported (nebulizing gas 6 L/min, heating gas 10 L/min, drying gas 12 L/min; interface 130 °C; DL 150 °C; heat block 100 °C). Multiple-reaction monitoring (MRM) transitions and dwell times optimized for each analyte; 13C-labelled internal standards used for HAAs.
• Calibration and standards: neat calibration standards prepared from 0.1 to 100 ppb (ranges varied by analyte). Internal standards included several 13C-labelled HAAs. Performance was assessed in reagent water, tap water and LFSSM spiked samples.

Used Instrumentation

• Shimadzu Nexera X3 HPLC system with C18 analytical column.
• Shimadzu LCMS-8060RX triple-quadrupole mass spectrometer (CoreSpray ionization).

Main results and discussion

• Runtime and throughput: The method achieved separation and quantitation of all targets in a 15-minute runtime, greatly improving throughput relative to EPA Method 557 (56 minutes).
• Linearity: Calibration curves demonstrated excellent linearity across tested ranges (typical correlation coefficients r between ~0.9948 and 0.9996 for most analytes), with calibration ranges commonly spanning 0.5–100 ppb (some analytes 0.1–100 ppb or 2–100 ppb).
• Sensitivity and MDL: Method detection limits (MDLs) were low (examples: reagent water MDLs in the range ~0.17–1.09 ppb for various analytes; tap water MDLs slightly higher). Several analytes were below MDL in unspiked matrices. Exact MDLs varied by compound and matrix.
• Accuracy and recoveries: Recoveries in reagent water and tap water were excellent for most analytes, typically falling within ~90–110% with relative standard deviations generally low (RSD values commonly a few percent). Internal-standard recoveries ranged from ~95–110%.
• Matrix performance: The LFSSM (laboratory fortified synthetic sample matrix) and tap water evaluations showed the method can quantify targets in realistic matrices, though recoveries for bromate and chlorate in LFSSM indicated potential for improvement. The authors recommend using isotopically labeled oxyanions (e.g., Br18O3- and Cl18O3-) to better correct for matrix-induced bias for bromate and chlorate.
• Chromatography: Representative chromatograms demonstrated baseline separation of most HAAs and target compounds at a 5 ppb spiking level; selected figures compared spiked vs unspiked tap water and LFSSM vs laboratory reagent blanks.

Benefits and practical applications

• Reduced analysis time—improves laboratory throughput and lowers per-sample instrument time compared with the existing EPA IC-MS/MS method.
• Minimal sample preparation—simplifies workflow for routine monitoring in drinking water labs and utilities.
• High sensitivity and accuracy—suitable for compliance monitoring at regulatory concentration levels and for research studies of DBP formation.
• Flexible instrumentation—method implemented on a modern triple-quadrupole LC-MS/MS platform with common reverse-phase consumables and commercially available labeled standards for HAAs.

Future trends and potential uses

• Isotopically labeled oxyanion standards: Adoption of labeled bromate and chlorate internal standards (e.g., 18O-labeled species) to improve accuracy in complex matrices and LFSSM-like samples.
• Expanded target panels: Extension to additional DBPs or related polar ionic species using similar LC-MS/MS approaches with optimized sample preparation for ionic analytes.
• Automation and high-throughput workflows: Integration with autosamplers and batch processing for routine monitoring programs and large-scale surveys.
• Interlaboratory validation: Wider validation and cross-lab studies to compare with regulated methods (EPA 557) and to support acceptance for compliance monitoring where appropriate.

Conclusion

A reverse-phase LC-MS/MS method on the Shimadzu LCMS-8060RX was developed and validated for simultaneous determination of bromate, chlorate, dalapon and nine HAAs with a rapid 15-minute runtime. The method demonstrated excellent linearity, low MDLs, and accurate recoveries in reagent and tap water matrices. Matrix-related recovery challenges for bromate/chlorate can be mitigated by using dedicated isotopically labeled oxyanion internal standards. Overall, the approach provides a higher-throughput alternative to EPA Method 557 with comparable sensitivity and precision for routine drinking-water monitoring and research applications.

References

• U.S. Environmental Protection Agency. Method 557: Determination of Haloacetic Acids, Bromate, and Dalapon in Drinking Water by Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC-ESI-MS/MS). September 2009.
• U.S. Code of Federal Regulations, Appendix B to Part 136, Title 40 — Definition and Procedure for the Determination of the Method Detection Limit—Revision 2.